i just picked up a pair of Corsair HS1's and i cant say enough good things about them. They are really hard to beat for the pricepoint. They are crazy comfortable too, its like wearing pillows over your ears for comfort :)
Hard ocp just did a glowing review on them as well: Introduction - Corsair HS1 USB Gaming Headset Review | [H]ard|OCP

Can you give us a comparison though? What else have you tried? and what do you use them for?
and like many past USB headphone discussions, how much did it slow your cpu by? noticable?